In certain electric motors, internal cooling air can be circulated via a fan that is mounted to a main motor shaft, which can rotate at the same angular velocity as the motor itself. Various air baffles can be provided to guide the air to desired portions of the electric motor. In certain variable speed motors, an amount of heat dissipated at low speeds can be greater than the flow capability of the fan. Because a total amount of airflow through a fan dramatically decreases with rotational speed, a cooling system that acts independently of the motor speed can be utilized. An independently driven auxiliary blower can provide a constant airflow regardless of the motor speed.
Numerous types of air enclosure assemblies can be associated with electric motors. Certain enclosure assemblies are associated with distinct cooling air flow patterns. Various cooling methods might be used to optimize the cooling at various speeds. Certain enclosures might not be provided with auxiliary blowers, and an auxiliary blower might be added later to the existing enclosure as an afterthought. As a result, different blowers might be used for certain distinct enclosure types, and a blower motor and fan might be ducted to the machine in a relatively complex manner.